In many ways, it could be said that ISIS are to the modern Middle East what the Nazis were to Europe in the 1930s and '40s. The rise of fascism that began in the '20s was a result of perceived "humiliation", economic deprivation, and loss of cultural identity: a violent counter-reaction to the modern Western values and socio-economic orthodoxy that was commonplace after the First World War.
In the search for simple answers, the Nazis in Germany took the ideas of Italian fascism, and applied them to their own circumstances. Adolf Hitler wanted to create a "thousand-year reich" that would extend from the Atlantic to the Urals. As he saw it, Germans were historically the "master race" of Europe, so they should take what was rightfully theirs: subdue the nations of the "lesser" Europeans, and cleanse Europe of Jews, who he saw as behind a worldwide conspiracy against Germany.

Change some of the names, and the ideology of ISIS is little different: Modern-day "Islamofascists" have created a brutal, despotic, anti-Western de facto state in the heart of the Middle East, and will use any means at its disposal to expand across the entire region; in the same way that fascism in Europe once brutally expanded across the entire continent, Islamofascism has the same aims today in the Middle East. Islamofascism is a reality, not a point of view: Osama Bin Laden and Al-Qaeda were the forerunners of ISIS, and ISIS are simply a more updated, tech-savvy offshoot of the same ideology. The only difference is that ISIS are applying their selfsame ideology with greater efficiency on the ground, and have honed to brutal near-perfection their methods of recruitment, warfare, and the iron fist of how to govern conquered territory, with a combination of "charity" and the ruthless application of power. Also, having lots of money to pass around - through oil revenues and the product of mass larceny - doesn't do any harm, either.

The irony here is that Al-Qaeda - once the most-feared terror group in the world - are now looking somewhat irrelevant compared to ISIS (as brilliantly summarized by John Oliver here); in the same way that Hitler's brutal form of fascism made Mussolini's earlier ideas seem "quaint" by comparison?

Here to stay?

No-one in the West has a real plan of how to defeat ISIS. Part of the problem is that ISIS appeals to disaffected Sunnis in Iraq and Syria in the same way that the Nazis held an appeal to large segments of German society in the 1930s. This is not to say that masses of Sunnis have suddenly become Islamic extremists: like the Germans in the thirties, they simply have little alternative on the ground, and would rather hold their noses to the reality rather than choose the chaotic alternative. They are not going to rise up against ISIS, because there is no-one who can rise to fill the hole that ISIS have filled in the Middle East.

For foreseeable future, ISIS and their "Islamic State" look to be a semi-permanent feature of the new
Middle East. As the Nazis filled the hole left by the weak authority of Weimar Germany left by Versailles, modern-day ISIS claim their legitimacy comes from the injustice of the Sykes-Picot Treaty that divided up the Sunnis of the Levant and Mesopotamia between Iraq and Syria. This is the core of their claim to be the representatives of Sunni Islamic values (whatever they may be).

The campaign to defeat ISIS isn't helped by the politics and rivalries of the Middle East. Turkey, a key member of NATO, seems to be turning a blind eye to ISIS: Ankara's policy seems to be a case of live-and-let-live; allowing recruits from Europe pass almost without hindrance across Turkey's border with Syria, and meanwhile seeming to give ISIS a free rein for its adherents to operate in the south of Turkey, moving against Syrian exiles that oppose them. While it many be too much of a stretch to say that this is because of shared Sunni Islamic values, it is more likely the case that the Turkish authorities (rightly) fear the consequences of going against ISIS: the thought of terrorist outrages in Turkish resorts would fill the government with dread. In this very real sense, Turkey's hands are tied. It is partly for this reason why they did so little to help the beseiged Syrian Kurdish town of Kobani, just across its border.